Process for improving the chemical and/or physical properties of a yarn or fabric

ABSTRACT

A process for improving the chemical and/or the physical properties of a yarn which comprises the step of applying a chitosan-based reinforcement product, a later step of crosslinking the chitosan and a partial and calibrated desizing step for removing the crosslinked chitosan, and the desizing step being carried out by mechanical process.

The present invention relates to a process for improving the chemicaland/or physical properties of a yarn or fabric, preferably a thin yarnor fabric made from natural animal fibers, vegetable fibers, syntheticpolymer fibers and/or man-made natural polymer fibers, used at purestate or blended together

As used herein, the term weaving shall be intended to cover bothwarp-and-weft weaving and knit-weaving.

As used herein, for example:

-   -   a thin yarn is intended to cover yarns having a yarn count        ranging from 50 to 200 Nm;    -   animal fibers are intended to cover fibers obtained from insects        (e.g. silkworm) or from fleece (e.g. wool, alpaca, vicuna,        cashmere, etc.);    -   vegetable fibers are intended to cover all the fibers obtained        from plants, shrubs, inflorescences, leaves (such as ramie,        bamboo, cotton, linen, etc.).

Thin yarns of the above mentioned type are known to be difficult toweave together, due to their thinness which makes them prone to breakingduring weaving.

For this reason a weaving technique is known in the art, e.g. from WO2013/057723, which includes the steps of applying a reinforcementsolution comprising chitosan and/or derivatives thereof to the fibers ofthe yarn, crosslinking the chitosan and/or derivatives thereof, e.g. byexposure to UV radiation and a desizing step, for removing the chitosanand/or derivatives thereof, as well as a partial and calibrated desizingstep for removal of both the chitosan and/or derivatives thereof aftercrosslinking.

It shall be noted in this respect that chitosan and/or its derivativesare easily removed because chitosan and/or its derivatives are solubleunder appropriate conditions, such removal being simply obtained bysubmitting the yarn or fabric to a washing step or one of the usualfinishing steps, e.g. a dyeing step obtained by immersing the fibers ina suitable dyeing solution at temperatures above 60° C.

Conversely, the crosslinked chitosan and/or crosslinked chitosanderivatives generate a water-insoluble crosslinked polymer which remainspermanently anchored to the fibers even after a number of successivewashing steps with hot and/or soapy water or after a hot-dyeing step.

Particularly, crosslinking of chitosan and/or derivatives thereof canincrease cohesion thereof to the fibers of the yarns. Particularly, thecrosslinked polymer resulting from crosslinking of chitosan and/orderivatives thereof is applied to the treated fibers in substantiallyundissolvable and durable fashion. The presence of this crosslinkedpolymer resulting from crosslinking of chitosan and/or derivativesthereof can:

-   -   impart a considerable physico-mechanical resistance to the yarn;    -   provide a sanitizing, antifelting and antibacterial effect to        the fibers, as well as    -   substantially improving finish affinity, particularly dye and        print affinity, especially to reactive dyes reacting with —OH        and —NH₂ groups.

In order to obtain yarns or fabrics with fibers having both the abovementioned advantages and the initial softness, volume, gloss andlightness properties as required, the amount of such crosslinked polymerresulting from crosslinking of chitosan and/or derivatives thereof onthe fibers shall not exceed the amount that is strictly sufficient toobtain the required benefits. Thus, for example, any excess of suchcrosslinked polymer on the fibers will cause the drawback that the yarnsand fabrics will exhibit a high resistance but also excessive rigidity.

Therefore, a need is felt for a partial and calibrated desizing step,for removing the crosslinked polymer resulting from crosslinking ofchitosan and/or derivatives thereof from the fibers of the yarn orfabric.

According to the prior art, such desizing step may be:

-   -   an enzymatic desizing step, preferably using amylase and/or        cellulase enzymes, within the range of pHs, temperatures and        activities specific to the enzyme and the relevant substrate or    -   a chemical desizing step, e.g. using hydrolyzing acids,        preferably diluted hydrochloric and/or sulfuric acid.

Concerning these desizing techniques for partial and calibrated removalof the crosslinked polymer resulting from crosslinking of chitosanand/or derivatives thereof from the fibers of the yarn or fabric, itshall be noted that they cannot be readily implemented, as preventivetests should be made for each different type of fiber to be treated.Furthermore, it shall be noted that the possibility of implementing suchpartial and calibrated desizing step by enzymatic or chemical proceduresrequires the introduction of special equipment or parts in the spinningand/or weaving lines, which are not typically provided, in other wordsthese techniques require the provision of a special production line.

Therefore, the invention is based on the problem of conceiving andproviding a process for improving the chemical and/or physicalproperties of a yarn or fabric, to fulfill the above need, whileobviating the above prior art drawbacks.

This problem is solved by a process for improving the chemical and/orphysical properties of a yarn, particularly a fine yarn, or a fabric asdefined in claim 1.

In a further aspect, the invention also relates to the use of areinforcement product comprising a composition of chitosan and/orderivatives thereof as defined in claim 15.

According to the invention, the yarn, which is preferably a fine yarn,comprises natural animal fibers and/or vegetable fibers, and/or man-madenatural polymer fibers and/or man-made natural crosslinked polymerfibers, used at pure state or blended together.

EXAMPLE 1

A process of the invention for improving the chemical and/or physicalproperties of a yarn made from natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers, at purestate or blended together, comprises the steps of:

a) providing a yarn made of natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers, at purestate or blended together;

b) preparing a sizing solution comprising a composition of chitosanand/or derivatives thereof as a reinforcement product;

c) sizing said yarn with said sizing solution to apply saidreinforcement product comprising chitosan and/or derivatives thereof tothe fibers of said yarn by at least partial impregnation and/or coating;

d) at least partially crosslinking the chitosan and/or derivativesthereof of said reinforcement product applied to the fibers by saidsizing step c), to obtain a crosslinked reinforcement polymer from saidchitosan and/or derivatives thereof, said polymer being permanentlyanchored to the fibers of said yarn and

e) performing a desizing step, for partial and calibrated removal ofsaid crosslinked reinforcement polymer derived from chitosan and/orderivatives thereof, and anchored to the fibers of said yarn, from suchfibers of said yarn.

Advantageously, the above mentioned desizing step e), for partial andcalibrated removal of said crosslinked reinforcement polymer derivedfrom chitosan and/or derivatives thereof from such fibers of said yarnis carried out by mechanical means.

The yarn obtained by the above described process steps b), c), d) and e)is a yarn having improved mechanical strength, remarkable sanitizing,antibacterial and antifelting properties and an excellent finishaffinity (e.g. dye and print affinity), partial and calibrated desizingfor removal of the crosslinked polymer being advantageously obtainedsimply and quickly by mechanical means.

EXAMPLE 2

A process for improving the chemical and/or physical properties of afabric or knit comprising yarns made from natural animal fibers,vegetable fibers, synthetic polymer fibers and/or man-made naturalpolymer fibers, at pure state or blended together, comprising a step ofwarp-and-weft weaving of said yarns or a step of knitting of said yarns,wherein at least one or both of the warp and weft yarns, preferably thewarp yarn only, used in this weaving step or a yarn used in saidknitting step, is a yarn that undergoes the following process steps:

a) providing a yarn made of natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers, at purestate or blended together;

b) preparing a sizing solution comprising a composition of chitosanand/or derivatives thereof as a reinforcement product;

c) sizing said yarn with said sizing solution to apply saidreinforcement product comprising chitosan and/or derivatives thereof tothe fibers of said yarn by at least partial impregnation and/or coatingand

d) at least partially crosslinking the chitosan and/or derivativesthereof of said reinforcement product applied to the fibers by saidsizing step c), to obtain a crosslinked reinforcement polymer from saidchitosan and/or derivatives thereof, said polymer being permanentlyanchored to the fibers of said yarn.

After said crosslinking step d), the yarn undergoes a step f) ofwarp-and-weft weaving of said yarns or a step of knitting of said yarns,wherein one or both of the warp and weft yarns, preferably the warp yarnonly, used in this weaving step or in said knitting step, is a yarn thatundergoes said process steps b), c) and d).

After said weaving or knitting step f), the fabric or knit so obtainedundergo a desizing step g) with partial and calibrated removal of saidcrosslinked reinforcement polymer derived from chitosan and/orderivatives thereof, from the fibers of the fabric or knit.

Advantageously, the above mentioned desizing step g) with partial andcalibrated removal of said crosslinked reinforcement polymer derivedfrom chitosan and/or derivatives thereof from such fibers of said yarnis at least partially carried out by acting upon said fibers bymechanical means.

EXAMPLE 3

A process for improving the chemical and/or physical properties of afabric, knit or garment comprising at least one yarnmade from naturalanimal fibers, vegetable fibers, synthetic polymer fibers and/orman-made natural polymer fibers, at pure state or blended together. Thisprocess comprises the steps of:

h) providing a finished fabric, knit or garment comprising at least oneyarn made of natural animal fibers, vegetable fibers, synthetic polymerfibers and/or man-made natural polymer fibers, at pure state or blendedtogether;

b) preparing a sizing solution comprising a composition of chitosanand/or derivatives thereof as a reinforcement product;

i) sizing said fabric, knit or garment with said sizing solution toapply said reinforcement product comprising chitosan and/or derivativesthereof to the fibers of said fabric, knit or garment by at leastpartial impregnation and/or coating;

l) after said sizing step i), crosslinking the chitosan and/orderivatives thereof of said chitosan composition to obtain a crosslinkedpolymer from said chitosan and/or derivatives thereof, which ispermanently anchored to the fibers of said fabric, knit or garment and

m) after said step 1) of at least partially crosslinking the chitosanand/or derivatives thereof of said composition, performing a desizingstep with partial and calibrated removal of said crosslinked polymerderived from chitosan and/or derivatives thereof, from the fibers ofsaid fabric, knit or garment.

Advantageously, the above mentioned desizing step m) with partial andcalibrated removal of said crosslinked reinforcement polymer derivedfrom chitosan and/or derivatives thereof from the fibers of said fabric,knit or garment is at least partially carried out by acting upon saidfibers by mechanical means.

Therefore, according to the invention, in all the above describedexamples, the partial and calibrated desizing step (i.e. a sizing stepthat does not involve complete removal of the crosslinked polymerapplied on the fibers), is at least partially carried out by mechanicaldesizing, whereby the fibers to be desized are physically acted upon byabrasion, rubbing, brushing and/or by treatments adapted to remove partof the crosslinked chitosan and/or chitosan-derived polymer from thefibers, such as by ultrasonic treatment.

Advantageously, said mechanical abrasion and/or rubbing treatment forpartial and calibrated removal of the crosslinked chitosan and/orchitosan-derived polymer may be carried out on the yarn during weaving,e.g. by sliding the yarn in contact with special rigid surfaces. Theserigid surfaces may consist of the dent and slaying surfaces of a reed,eye holes, namely healds or Jacquard heddles, through which the yarn isslid during weaving, surfaces of rollers contacted by the sliding yarnduring weaving, bristles of a brush, and others.

These mechanical abrasion and/or rubbing treatments may be carried outon yarn fibers even after the weaving or knitting step, i.e. by directlyacting upon the finished fabric or knit. In this case, these mechanicaltreatments are advantageously carried out by brushing the fabric or theknit.

According to an alternative embodiment, the partial and calibratedmechanical desizing step for removing the crosslinked chitosan and/orchitosan-derived polymer from the fibers of the yarn or fabric or knit,may be carried out by ultrasonic treatment of such fibers. Convenientlythis may take place, for example, with the fibers of the yarn, fabric orknit immersed in a liquid in which an ultrasound-emitting probe isintroduced.

Advantageously, the ultrasonic treatment of the fibers may be carriedout at the same time as a step of weaving or finishing during which thefibers are already immersed in a bath, for example during a step ofwashing the fibers or knit or during a dyeing step.

It shall be understood from the above that, with the possibility ofcarrying out the desizing step by mechanical means, no furtherprocessing step shall be added to those required for producing the yarn,fabric or knit, and no further special equipment shall be added to theone that is specially required for partial and calibrated desizing forremoval of the crosslinked chitosan and/or chitosan-derived polymer.

The possibility of carrying out partial and calibrated mechanicaldesizing for removal of the crosslinked polymer on the fibers does notexclude the possibility that such partial and calibrated desizing stepmay be also carried out before or after as:

-   -   an enzymatic desizing step, preferably using amylase and/or        cellulase enzymes, within the range of pHs, temperatures and        activities specific to the enzyme and the relevant substrate or    -   a chemical desizing step, e.g. using hydrolyzing acids,        preferably diluted hydrochloric and/or sulfuric acid.

Particularly, the partial and calibrated mechanical desizing step may becarried out in addition to a chemical or an enzymatic desizing step.

The partial and calibrated desizing step using ultrasounds may becarried out at the same time as a partial and calibrated chemical orenzymatic desizing step, using the same bath, which will afford asynergy of effects between the different desizing steps.

According to a preferred embodiment, after the sizing step, the step ofcrosslinking the chitosan and/or its derivatives is preceded by a a stepof drying the fibers of the yarn, fabric or knit and the crosslinkedchitosan and/or chitosan-derived polymer applied to the fibers of theyarn, fabric or knit, to thereby facilitate the later chitosancrosslinking step.

Preferably, the chitosan crosslinking step is carried out by a step ofUV exposure of the fibers of the yarn, fabric, knit or garment, chemicalcrosslinking being also possibly provided.

Preferably, the step of sizing said finished fabric, knit or garment iscarried out by foularding and/or impregnation of the finished fabric,knit or garment in the sizing solution.

Preferably, such step of sizing the fibers is carried out using a sizingsolution comprising:

-   -   low-molecular-weight chitosan;    -   acid aqueous solution;    -   radical photoinitiator.

Preferably, the chitosan in use has a low molecular weight, e.g. of theorder of 150,000 Da. Particularly, it is a chitosan with 75÷85% degreeof deacetylation; 20÷200 cps viscosity at a concentration range of0.5÷10% w/v, preferably 0.8÷3% w/v, more preferably 1% w/v;

Preferably, said acid aqueous solution comprises acetic acid at aconcentration of 1.5÷3.8% v/v, preferably at a concentration of1.8÷2.22% v/v, more preferably at a concentration of 2% v/v.

Preferably, said step of sizing the fibers of the yarn, fabric, knit orgarment with said sizing solution is carried out with a bath ratioranging from 1÷7 to 1÷35, preferably with a bath ratio ranging from 1÷10to 1÷30, more preferably with a bath ratio ranging from 1÷16 to 1÷24.

Preferably, said step of sizing said finished fabric, knit or garmentwith said sizing solution is carried out with a bath ratio ranging from1÷7 to 1÷35, preferably with a bath ratio ranging from 1÷10 to 1÷30,more preferably with a bath ratio ranging from 1÷16 to 1÷24.

Preferably, this desizing step, with partial and calibrated removal ofsaid crosslinked chitosan-derived reinforced polymer from the fibers ofsaid yarn, leaves said crosslinked chitosan-derived reinforcementpolymer on the fibers of said yarn subjected to said sizing step, in anamount of 0.3÷9% w/w based on the dry weight of the yarn after saidsizing step.

The above disclosure is susceptible to a number of changes and variantswithin the inventive concept, as outlined by the annexed claims.

Thus, for example, the yarn, which is preferably a thin yarn, may alsocomprise a doubled yarn with a monofilament or multifilament yarncontaining chitosan or be doubled with a yarn made of discontinuousfibers, containing chitosan.

1-15. (canceled)
 16. A process for improving chemical and/or physicalproperties of a yarn made from natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers, eitherin a pure state or blended together, the process comprising: a)providing a yarn made of natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers, eitherin the pure state or a blended together; b) preparing a sizing solutioncomprising a composition of chitosan and/or derivatives thereof as areinforcement product; c) sizing the yarn with the sizing solution toapply the reinforcement product comprising chitosan and/or derivativesthereof to the fibers of the yarn by at least partial impregnationand/or coating; d) at least partially crosslinking the chitosan and/orderivatives thereof of the reinforcement product applied to the fibersby the sizing step c), to obtain a crosslinked reinforcement polymerfrom the chitosan and/or derivatives thereof, and the polymer beingpermanently anchored to the fibers of the yarn and e) performing adesizing step, for partial and calibrated removal of the crosslinkedreinforcement polymer derived from chitosan and/or derivatives thereof,and anchored to the fibers of the yarn, from such fibers of the yarn,wherein the above mentioned desizing step e) for partial and calibratedremoval of the crosslinked reinforcement polymer derived from chitosanand/or derivatives thereof from such fibers of the yarn is carried outby mechanical means,
 17. A process for improving the chemical and/orphysical properties of a fabric or knit comprising yarns made fromnatural animal fibers, vegetable fibers, synthetic polymer fibers and/orman-made natural polymer fibers, either in a pure state or blendedtogether, the process comprising: a) providing a yarn made of naturalanimal fibers, vegetable fibers, synthetic polymer fibers and/orman-made natural polymer fibers, either in the pure state or blendedtogether; b) preparing a sizing solution comprising a composition ofchitosan and/or derivatives thereof as a reinforcement product; c)sizing the yarn with the sizing solution to apply the reinforcementproduct comprising chitosan and/or derivatives thereof to the fibers ofthe yarn by at least partial impregnation and/or coating; d) at leastpartially crosslinking the chitosan and/or derivatives thereof of thereinforcement product applied to the fibers by the sizing step c), toobtain a crosslinked reinforcement polymer from the chitosan and/orderivatives thereof, and the polymer being permanently anchored to thefibers of the yarn; e) performing a step of warp-and-weft weaving of theyarns or a step of knitting of the yarns, wherein one or both of thewarp and weft yarns, preferably the warp yarn only, used in this weavingstep or in the knitting step, is a yarn that undergoes the process stepsb), c) and d); f) performing a desizing step, for partial and calibratedremoval of the crosslinked reinforcement polymer derived from chitosanand/or derivatives thereof, from the fibers of the fabric or knit,wherein the desizing step g) with partial and calibrated removal of thecrosslinked reinforcement polymer derived from chitosan and/orderivatives thereof from such fibers of the yarn is at least partiallycarried out by acting upon the fibers by mechanical means.
 18. A processfor improving the chemical and/or physical properties of a fabric, knitor garment comprising at least one yarn made from natural animal fibers,vegetable fibers, synthetic polymer fibers and/or man-made naturalpolymer fibers, either in a pure state or blended together, the processcomprising: a) providing a finished fabric, knit or garment comprisingat least one yarn made of natural animal fibers, vegetable fibers,synthetic polymer fibers and/or man-made natural polymer fibers at purestate or blended together: b) preparing a sizing solution comprising acomposition of chitosan and/or derivatives thereof as a reinforcementproduct; c) sizing the fabric, knit or garment with the sizing solutionto apply the reinforcement product comprising chitosan and/orderivatives thereof to the fibers of the fabric, knit or garment by atleast partial impregnation and/or coating; d) crosslinking the chitosanand/or derivatives thereof of the chitosan composition to obtain acrosslinked polymer from the chitosan and/or derivatives thereof, whichis permanently anchored to the fibers of the fabric, knit or garment ande) performing a desizing step, with partial and calibrated removal ofthe crosslinked polymer derived from chitosan and/or derivativesthereof, from the fibers of the fabric, knit or garment, wherein thedesizing step e) with partial and calibrated removal of the crosslinkedreinforcement polymer derived from chitosan and/or derivatives thereoffrom the fibers of the fabric, knit or garment, is at least partiallycarried out by acting upon the fibers by mechanical means.
 19. Theprocess according to claim 16, wherein the partial and calibrateddesizing step is at least partially carried out by mechanical desizing,whereby the fibers to be desized are physically acted upon by one ofabrasion, rubbing, brushing and/or by treatments adapted to remove partof the crosslinked chitosan and/or chitosan-derived polymer from thefibers.
 20. The process according to claim 19, wherein the mechanicaldesizing step for physically acting upon the fibers to be desized byabrasion and/or rubbing is carried out on the yarn during the weavingstep.
 21. The process according to claim 19, wherein the mechanicaldesizing step for physically acting upon the fibers to be desized byabrasion and/or rubbing is carried out by sliding the yarn in contactwith rigid surfaces.
 22. The process according to claim 21, wherein therigid surfaces consist of the surfaces of the reed dents, eye holesthrough which the yarn is slid during weaving, surfaces of rollerscontacted by the yarn and/or the bristles of a brush.
 23. The processaccording to claim 16, wherein the partial and calibrated mechanicaldesizing step for removing the crosslinked chitosan and/orchitosan-derived polymer from the fibers is carried out by ultrasonictreatment of such fibers while the fibers are immersed in a bath. 24.The process according to claim 23, wherein the ultrasonic treatment ofthe fibers is carried out at the same time as a step weaving orfinishing processing step, during which the fibers are already immersedin the bath.
 25. The process according to claim 16, wherein the partialand calibrated mechanical desizing step is carried out in addition to achemical or an enzymatic desizing step.
 26. The process according to 16,wherein the partial and calibrated mechanical desizing step byultrasonic treatment of the fibers upon which the crosslinked chitosanand/or chitosan-derived polymer is applied is carried out substantiallyat the same time as the partial and calibrated chemical or enzymaticdesizing step, using a same bath,
 27. The process according to claim 16,wherein the step of crosslinking the chitosan of the reinforcementproduct applied to the fibers is preceded by the step of drying thefibers of the yarn and the chitosan of the reinforcement product appliedto the fibers of the yarn, to thereby facilitate the later chitosancrosslinking step.
 28. A use of a reinforcement product comprising acomposition of chitosan and/or derivatives thereof in the processaccording to claim 16, for improving the chemical and/or physicalproperties of a yarn.
 29. The process according to claim 17, wherein thepartial and calibrated desizing step is at least partially carried outby mechanical desizing, whereby the fibers to be desized are physicallyacted upon by at least one of abrasion, rubbing, brushing and/or bytreatments adapted to remove part of the crosslinked chitosan and/orchitosan-derived polymer from the fibers.
 30. The process according toclaim 29, wherein the mechanical desizing step for physically actingupon the fibers to be desized by abrasion and/or rubbing is carried outon the yarn during the weaving step.
 31. The process according to claim29, wherein the mechanical desizing step for physically acting upon thefibers to be desized by at least one of abrasion and/or rubbing iscarried out by sliding the yarn in contact with rigid surfaces.
 32. Theprocess according to claim 31, wherein the rigid surfaces consist of thesurfaces of the reed dents, eye holes through which the yarn is slidduring weaving, surfaces of rollers contacted by the yarn and/or thebristles of a brush.
 33. The process according to claim 29, wherein themechanical desizing step for physically acting upon the fibers to bedesized by abrasion and/or rubbing is carried out on the fabric, knit orgarment.
 34. The process according to claim 33, wherein the mechanicaldesizing step by abrasion and/or rubbing is carried out by brushing thefabric, knit and/or garment, or by sliding the fabric in contact withrigid surfaces.
 35. The process according to claim 17, wherein thepartial and calibrated mechanical desizing step for removing thecrosslinked chitosan and/or chitosan-derived polymer from the fibers iscarried out by ultrasonic treatment of such fibers while the fibers areimmersed in a bath.
 36. The process according to claim 35, wherein theultrasonic treatment of the fibers is carried out at a same time as astep weaving or finishing processing step, during which the fibers arealready immersed in a bath.
 37. The process according to claim 17,wherein the partial and calibrated mechanical desizing step is carriedout in addition to a chemical or enzymatic desizing step.
 38. Theprocess according to claim 17, wherein the partial and calibratedmechanical desizing step by ultrasonic treatment of the fibers uponwhich the crosslinked chitosan and/or chitosan-derived polymer isapplied is carried out substantially at the same time as the partial andcalibrated chemical or enzymatic desizing step, using the same bath. 39.The process for improving the chemical and/or physical properties of ayarn according to claim 17, wherein the step of crosslinking thechitosan of the reinforcement product applied to the fibers is precededby the step of drying the fibers of the yarn and the chitosan of thereinforcement product applied to the fibers of the yarn, to therebyfacilitate the later chitosan crosslinking step.
 40. A use of areinforcement product comprising a composition of chitosan and/orderivatives thereof in the process according to claim 29 for improvingthe chemical and/or physical properties of a yarn.
 41. The processaccording to claim 18, wherein the partial and calibrated desizing stepis at least partially carried out by mechanical desizing, whereby thefibers to be desized are physically acted upon by at least one ofabrasion, rubbing, brushing and/or by treatments adapted to remove partof the crosslinked chitosan and/or chitosan-derived polymer from thefibers.
 42. The process according to claim 41, wherein the mechanicaldesizing step for physically acting upon the fibers to be desized byabrasion and/or rubbing is carried out on the fabric, knit or garment.43. The process according to claim 42, wherein the mechanical desizingstep by abrasion and/or rubbing is carried out by brushing the fabric,knit and/or garment, or by sliding the fabric in contact with rigidsurfaces.
 44. The process according to claim 18, wherein the partial andcalibrated mechanical desizing step for removing the crosslinkedchitosan and/or chitosan-derived polymer from the fibers is carried outby ultrasonic treatment of such fibers, while the fibers are immersed ina bath.
 45. The process according to claim 44, wherein the ultrasonictreatment of the fibers is carried out at a same time as a step weavingor finishing processing step, during which the fibers are alreadyimmersed in a bath.
 46. The process according to claim 18, wherein thepartial and calibrated mechanical desizing step is carried out inaddition to a chemical or an enzymatic desizing step.
 47. The processaccording to claim 18, wherein the partial and calibrated mechanicaldesizing step by ultrasonic treatment of the fibers upon which thecrosslinked chitosan and/or chitosan-derived polymer is applied iscarried out substantially at a same time as the partial and calibratedchemical or enzymatic desizing step, using a same bath.
 48. The processaccording to claim 18, wherein the step of crosslinking the chitosan ofthe reinforcement product applied to the fibers is preceded by the stepof drying the fibers of the yarn and the chitosan of the reinforcementproduct applied to the fibers of the yarn, to thereby facilitate thelater chitosan crosslinking step.